Reshad Jones‘ season could already be over. The Dolphins fear that the safety tore his rotator cuff, sources tell Ian Rapoport of NFL.com tweets. Jones is currently undergoing tests to determine the severity of his injury.

Jones was instrumental in the Dolphins’ surprising 30-15 win over the Steelers on Sunday. If the Dolphins lose the best player in their secondary for the season, it’s hard to see them building momentum off of that win and turning their season around.

Jones, 28, has 51 total tackles, four passes defensed, one interception, and even half a sack through six games this season. The advanced metrics at Pro Football Focus have him ranked as the third-best safety in the NFL so far this year with a strong 88.5 overall grade. Miami has been leaning on him heavily as evidenced by his 437 total snaps this season.